Comparative analysis of clinical trials and evidence-based treatment algorithm in pulmonary arterial hypertension

Differences in health policies for drug availability in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension across Latin America

Treatment for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in Latin America differs between countries, with regard to disease etiology, health insurance coverage, and drug availability. A group of experts from Latin America, met to share regional experiences and propose possible lines of collaboration. The available evidence, regional clinical practice data, and the global context of the proceedings of the 6th World Symposium on Pulmonary Hypertension, held in Nice, France, in February 2018, were analyzed. Here, we discuss some priority concepts identified that could guide transnational interaction and research strategies in Latin America: (1) despite being evidence‐based, the 6th World Symposium on Pulmonary Hypertension proceedings may not be applicable in Latin American countries; (2) proactive identification and diagnosis of patients in Latin America is needed; (3) education of physicians and standardization of appropriate treatment for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is vital; (4) our clinical experience for the treatment strategy for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is based on drug availability in Argentina, Brazil, Colombia and México; (5) there are difficulties inherent to the consultation of patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, and access to treatment; (6) the importance of data generation and research of Latin American‐specific issues related to pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is highlighted.

Strategies for optimizing intravenous prostacyclin-analog therapy in patients with pulmonary arterial hypertension

INTRODUCTION

Intravenous prostacyclin-analogs (PCA, e.g. epoprostenol, treprostinil, iloprost) have become an essential part in the therapy of patients with pulmonary hypertension (PH), mainly pulmonary arterial hypertension (PAH). They show considerable differences in pharmacology. A combination therapy including intravenous drugs is regarded as the 'gold standard' in most of PAH patients.

AREAS COVERED

This review discusses and summarizes the studies and concepts on which this therapy is based. To date, intravenous prostacyclin-analogs are mainly administered when standard therapy fails to improve patients to low-risk status. However, preliminary data from uncontrolled studies suggest that an 'upfront triple' therapy including intravenous or subcutaneous prostacyclin-analogs could be preferable in selected patients.

EXPERT OPINION

Various IV PCA have been evaluated in the treatment of patients with PAH. Today, combination therapy is the 'gold standard' for the majority of patients. Intravenous PCA is recommended from functional class III onwards. Timing of its initiation is still a point of discussion. An escalation of therapy to IV or SC PCA is always necessary if a low-risk status cannot be achieved with other targeted therapies. Preliminary data suggest that selected patients could benefit from an 'upfront triple' therapy. Controlled studies on which such recommendation could be based are lacking.

Application of 7.0 T ultra-high-field MRI in evaluating the structure and function of the right ventricle of the heart in rats under a chronic hypoxic environment at high altitude

Background

Long-term exposure to a high-altitude environment with low pressure and low oxygen can cause abnormalities in the structure and function of the heart, in particular the right ventricle. Monitoring the structure and function of the right ventricle is therefore essential for early diagnosis and prognosis of high-altitude heart-related diseases. In this study, 7.0 T MRI is used to detect cardiac structure and function indicators of rats in natural plateau and plain environments.

Methods

Rats in two groups were raised in different environments from 6 weeks of age for a period of 12 weeks. At 18 weeks of age both groups underwent 7.0 T cardiac magnetic resonance (CMR) scanning. Professional cardiac post-processing software was used to analyze right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), right ventricular stroke volume (RVSV), right ventricular ejection fraction (RVEF), Right ventricular end-diastolic myocardial mass (RV Myo mass, diast), Right ventricular end-systolic myocardial mass (RV Myo mass, syst), tricuspid valve end-diastolic caliber (TVD), tricuspid valve end-systolic caliber (TVS), right ventricular end-systolic long-axis (RVESL) and right ventricular end-diastolic long-axis (RVEDL). Prior to the CMR scan, blood was collected from the two groups of rats for evaluation of blood indicators. After the scan, the rats were sacrificed and the myocardial tissue morphology observed under a light microscope.

Results

In the group of rats subject to chronic hypoxia at high altitude for 12 weeks (the plateau group), red blood cell (RBC) count, hemoglobin (HGB) and hematocrit (HCT) increased (P<0.05); RVEDV, RVESV, RVSV, RV Myo mass (diast), RV Myo mass (syst), TVS, RVESL, and RVEDL also increased (P<0.05). Observation of the right ventricle of rats in the plateau group using a light microscope mainly showed a slightly widened myocardial space, myocardial cell turbidity, vacuolar degeneration, myocardial interstitial edema, vascular congestion and a small amount of inflammatory cell infiltration.

Conclusions

The importance of ultra-high-field MRI for monitoring the early stages of rat heart injury has been demonstrated by studying the changes in the structure and function of the right ventricle of rats subject to chronic hypoxia at high altitude over a period of 12 weeks.

Contemporary Pharmacotherapeutic Approach in Pulmonary Arterial Hypertension

Since the 1973 World Symposium on Pulmonary Hypertension, advancements in the understanding of pathophysiology and pathobiology have led to a myriad of pharmacotherapies for the disease. This article journeys through the development of therapeutic approaches for pulmonary arterial hypertension.

Fick principle and exercise pulmonary hemodynamic determinants of the six-minute walk distance in pulmonary hypertension

The six-minute walk test is widely used to assess the severity and prognosis of pulmonary hypertension. However, the pathophysiology underlying a compromised six-minute walk distance is incompletely characterized. The purpose of this study is to evaluate the Fick principle and pulmonary hemodynamic determinants of the six-minute walk distance in patients with suspected pulmonary hypertension. Twenty-nine patients were retrospectively studied and underwent a right heart catheterization for the evaluation of suspected pulmonary hypertension. With the pulmonary artery catheter in place, patients were moved to a treadmill and completed a six-minute walk test. Fick cardiac output and indices of right heart afterload were calculated using continuous measurements of pulmonary vascular pressures, gas exchange, and mixed venous blood samples. Fifteen subjects who walked ≤ 348 m were compared to 14 subjects who walked > 348 m. Systemic oxygen delivery was impaired in six-minute walk distance ≤ 348 m compared to six-minute walk distance > 348 m (15.2 ± 6.2 vs. 23.2 ± 6.8 mL/kg/min, p < 0.01). Impaired oxygen delivery was due to a depressed cardiac index and decreased cardiac reserve demonstrated by the change in the stroke volume index (3.0 ± 14 vs. 17 ± 15 mL/min/m², p = 0.02). The six-minute walk distance positively correlated with oxygen delivery (r = 0.501, p = 0.006) and inversely correlated with oxygen extraction (r = 0.369, p = 0.049). A decreased six-minute walk distance was associated with an increased total pulmonary resistance (r = 0.502, p = 0.006) and pulmonary vascular resistance (r = 0.530, p = 0.003). In patients with suspected pulmonary hypertension, a decreased six-minute walk distance is due to compromised oxygen delivery, decreased cardiac reserve, and increased right ventricular afterload.

Combination of Dichloroacetate and Atorvastatin Regulates Excessive Proliferation and Oxidative Stress in Pulmonary Arterial Hypertension Development via p38 Signaling

Pulmonary arterial hypertension (PAH) is a lethal disease generally characterized by pulmonary artery remodeling. Mitochondrial metabolic disorders have been implicated as a critical regulator of excessively proliferative- and apoptosis-resistant phenotypes in pulmonary artery smooth muscle cells (PASMCs). Dichloroacetate (DCA) is an emerging drug that targets aerobic glycolysis in tumor cells. Atorvastatin (ATO) is widely used for hyperlipemia in various cardiovascular diseases. Considering that DCA and ATO regulate glucose and lipid metabolism, respectively, we hypothesized that the combination of DCA and ATO could be a potential treatment for PAH. A notable decrease in the right ventricular systolic pressure accompanied by reduced right heart hypertrophy was observed in the DCA/ATO combination treatment group compared with the monocrotaline treatment group. The DCA/ATO combination treatment alleviated vascular remodeling, thereby suppressing excessive PASMC proliferation and macrophage infiltration. In vitro, both DCA and ATO alone reduced PASMC viability by upregulating oxidative stress and lowering mitochondrial membrane potential. Surprisingly, when combined, DCA/ATO was able to decrease the levels of reactive oxygen species and cell apoptosis without compromising PASMC proliferation. Furthermore, suppression of the p38 pathway through the specific inhibitor SB203580 attenuated cell death and oxidative stress at a level consistent with that of DCA/ATO combination treatment. These observations suggested a complementary effect of DCA and ATO on rescuing PASMCs from a PAH phenotype through p38 activation via the regulation of mitochondrial-related cell death and oxidative stress. DCA in combination with ATO may represent a novel therapeutic strategy for PAH treatment.

Risk stratification and medical therapy of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) remains a severe clinical condition despite the availability over the past 15 years of multiple drugs interfering with the endothelin, nitric oxide and prostacyclin pathways. The recent progress observed in medical therapy of PAH is not, therefore, related to the discovery of new pathways, but to the development of new strategies for combination therapy and on escalation of treatments based on systematic assessment of clinical response. The current treatment strategy is based on the severity of the newly diagnosed PAH patient as assessed by a multiparametric risk stratification approach. Clinical, exercise, right ventricular function and haemodynamic parameters are combined to define a low-, intermediate- or high-risk status according to the expected 1-year mortality. The current treatment algorithm provides the most appropriate initial strategy, including monotherapy, or double or triple combination therapy. Further treatment escalation is required in case low-risk status is not achieved in planned follow-up assessments. Lung transplantation may be required in most advanced cases on maximal medical therapy.

Anticoagulation in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by molecular and pathologic alteration to the pulmonary circulation, resulting in increased pulmonary vascular resistance, right ventricular failure, and eventual death. Pharmacologic treatment of PAH consists of use of a multitude of pulmonary vasodilators, sometimes in combination. PAH has been associated with increased thrombosis and disrupted coagulation and fibrinolysis, making anticoagulation an attractive and frequently employed therapeutic modality. Observational studies have provided some insight into the therapeutic potential of anticoagulation in idiopathic PAH, but there is a distinct lack of well-controlled prospective trials. Due to the conflicting evidence, there is a large amount of heterogeneity in the application of therapeutic anticoagulation in PAH and further well-controlled prospective trials are needed to clarify its role in treating PAH.

Epoprostenol and pulmonary arterial hypertension: 20 years of clinical experience

Epoprostenol was the first therapy to be approved for the treatment of pulmonary arterial hypertension (PAH). In the 20 years since the introduction of this prostacyclin analogue, the outlook for patients with PAH has improved, with survival rates now double those from the era before the development of disease-specific treatments. Today, there are a large amount of data on the clinical role of prostacyclin treatments and a body of evidence attesting the efficacy of epoprostenol in improving exercise capacity, key haemodynamic parameters and PAH symptoms, as well as in reducing mortality. The place of epoprostenol in the therapeutic management of PAH continues to evolve, with the development of new formulations and use in combination with other drug classes. In this review, we provide a historical perspective on the first 20 years of epoprostenol, a therapy that led to evidence-based study of PAH-specific treatments and the subsequent expansion of treatment options for PAH.

The evolution of the place of epoprostenol in the management of pulmonary arterial hypertensionhttp://ow.ly/OkY3303N2CX

An epidemiological study of paediatric pulmonary hypertension in Turkey

OBJECTIVE

The present study aims to evaluate the epidemiological characteristics of paediatric pulmonary hypertension within the entire Turkish population over a period of 5 years using the registry of the National Health Insurance System.

METHODS

All individuals aged <18 years who were admitted to a Turkish hospital for the first time between 2009 and 2013 with a discharge diagnosis of idiopathic pulmonary hypertension and secondary pulmonary hypertension were identified.

RESULTS

The overall annual incidence of idiopathic pulmonary hypertension during childhood was 11.7 cases/million, whereas the overall annual incidence of secondary pulmonary hypertension during childhood was 9.5 cases/million. There was a gradual and significant increase in the annual incidence of idiopathic pulmonary hypertension and that of secondary pulmonary hypertension during the 5-year study period (p=0.001 for both). In the years 2012 and 2013, idiopathic pulmonary hypertension was significantly more frequent in children aged <2 years when compared with children aged above 2 years (p=0.002 for both). The male to female ratio was 1.2:1 for idiopathic pulmonary hypertension, whereas the female to male ratio was 1.1:1 for secondary pulmonary hypertension during childhood.

CONCLUSION

The incidence of paediatric pulmonary hypertension in Turkey is higher than those reported for the Western populations. Moreover, no female dominance could be observed. These discrepancies may be attributed to the differences in the study design, study cohort, timing of the study, and the definitions adopted for pulmonary hypertension classification.

Pulmonary artery ablation to treat pulmonary arterial hypertension: a case report

Introduction

Idiopathic pulmonary arterial hypertension is defined as a group of diseases characterized by a progressive increase in pulmonary vascular resistance that results in right heart failure and premature death. Although therapies exist to improve hemodynamic instability and symptoms, there is no cure for pulmonary arterial hypertension and it remains a life-threatening condition. A recent study performed in China reported, for the first time, the effect of pulmonary arterial denervation on functional capacity and hemodynamics in patients with refractory idiopathic pulmonary arterial hypertension.

Case presentation

We report a case of a 60-year-old white Brazilian man, with controlled hypertension and stage 2 obesity who complained of progressive fatigue with moderate to light exertion of approximately 1 year’s duration. During this period, he underwent myocardial perfusion scintigraphy without evidence of obstructive ischemic disease. He had no clinical evidence of systolic heart failure. He had undergone biological mitral valve replacement 3 years previously for mitral valve stenosis and ablation of atrioventricular nodal reentry tachycardia 18 months previously. At the time of valve replacement, he had no reported evidence of pulmonary arterial hypertension. His echocardiogram showed normal function of a mitral prosthesis, normal global left ventricular systolic function (left ventricular ejection fraction 62 % measured using the Teichholz method), stage I diastolic dysfunction, and a mean systolic pulmonary arterial blood pressure of 50 mmHg. In the 6-minute walk test, the patient walked 104 meters. Catheterization of his right heart chambers and pulmonary arteries confirmed the diagnosis of pulmonary hypertension. Electroanatomic reconstruction of the right ventricular outflow tract and pulmonary artery was performed under direct fluoroscopic visualization, and a merger was made with a formatted image of cardiac computed tomography angiography. Then we performed irrigated cardiac catheter ablation of the pulmonary trunk.

Conclusions

At the patient’s 3-month follow-up, he showed improvement in functional class for fatigue on major exertion, increased distance walked in the 6-minute walk test, and reductions in pressure of both the right cavities and the pulmonary artery. Currently, with 6 months of clinical follow-up, the patient has maintained his functional classification and is pedaling his bicycle.

The limits of oral therapy in pulmonary arterial hypertension management

Pulmonary arterial hypertension (PAH) is a devastating disease in which remodeling of the small pulmonary arteries leads to a progressive increase in pulmonary vascular resistance and right-sided heart failure. Over the past decade, new treatments for PAH, such as the use of ERAs, PDE-5 inhibitors and prostacyclin analogs, have brought about dramatic improvements in clinical outcomes. Epoprostenol infusion therapy has been shown to improve hemodynamics, functional status, and survival, and it remains the gold standard for treatment of patients with severe PAH. Many agents, approved for PAH are always delivered in pill form. Although oral therapy occupies an important position, it has some drawbacks and limitations in PAH management. For patients in World Health Organization functional class IV and with severe right heart failure, there are few data on the long-term survival of patients treated with oral medications. Further research, exploration, and clinical experience with oral therapy in severe PAH and combination therapy will redefine its position in PAH management.

Investigation of mutual pharmacokinetic interactions between macitentan, a novel endothelin receptor antagonist, and sildenafil in healthy subjects

AIM

To study the mutual pharmacokinetic interactions between macitentan, an endothelin receptor antagonist, and sildenafil in healthy male subjects.

METHODS

In this open-label, randomized, three way crossover study, 12 healthy male subjects received the following oral treatments: A) a loading dose of 30 mg macitentan on day 1 followed by 10 mg once daily for 3 days, B) sildenafil 20 mg three times a day for 3 days and a single 20 mg dose on day 4 and C) both treatments A and B concomitantly. Plasma concentration-time profiles of macitentan and its active metabolite ACT-132577 (treatments A and C) and sildenafil and its N-desmethyl metabolite (treatments B and C) were determined on day 4 and analyzed non-compartmentally.

RESULTS

The pharmacokinetics of macitentan were not affected by sildenafil. In the presence of sildenafil Cmax and AUCτ of the metabolite ACT-132577 decreased with geometric mean ratios (90% confidence interval (CI)) of 0.82 (0.76, 0.89) and 0.85 (90% CI 0.80, 0.91), respectively. In the presence of macitentan, plasma concentrations of sildenafil were higher than during treatment with sildenafil alone, resulting in increased Cmax and AUCτ values. The respective geometric mean ratios were 1.26 (90% CI 1.07, 1.48) and 1.15 (90% CI 0.94, 1.41). The pharmacokinetics of N-desmethylsildenafil were not affected by macitentan. All treatments were well tolerated.

CONCLUSION

A minor, not clinically relevant, pharmacokinetic interaction was observed between macitentan and sildenafil. Based on these results, no dose adjustment of either compound appears necessary during concomitant treatment with macitentan and sildenafil.

Bosentan added to sildenafil therapy in patients with pulmonary arterial hypertension

The safety and efficacy of adding bosentan to sildenafil in pulmonary arterial hypertension (PAH) patients was investigated.

In this prospective, double-blind, event-driven trial, symptomatic PAH patients receiving stable sildenafil (≥20 mg three times daily) for ≥3 months were randomised (1:1) to placebo or bosentan (125 mg twice daily). The composite primary end-point was the time to the first morbidity/mortality event, defined as all-cause death, hospitalisation for PAH worsening or intravenous prostanoid initiation, atrial septostomy, lung transplant, or PAH worsening. Secondary/exploratory end-points included change in 6-min walk distance and World Health Organization functional class at 16 weeks, change in N-terminal pro-brain natriuretic peptide (NT-proBNP) over time, and all-cause death.

Overall, 334 PAH patients were randomised to placebo (n=175) or bosentan (n=159). A primary end-point event occurred in 51.4% of patients randomised to placebo and 42.8% to bosentan (hazard ratio 0.83, 97.31% CI 0.58–1.19; p=0.2508). The mean between-treatment difference in 6-min walk distance at 16 weeks was +21.8 m (95% CI +5.9–37.8 m; p=0.0106). Except for NT-proBNP, no difference was observed for any other end-point. The safety profile of bosentan added to sildenafil was consistent with the known bosentan safety profile.

In COMPASS-2, adding bosentan to stable sildenafil therapy was not superior to sildenafil monotherapy in delaying the time to the first morbidity/mortality event.

Inhaled nitric oxide alters the distribution of blood flow in the healthy human lung, suggesting active hypoxic pulmonary vasoconstriction in normoxia

Hypoxic pulmonary vasoconstriction (HPV) is thought to actively regulate ventilation-perfusion (V̇a/Q̇) matching, reducing perfusion in regions of alveolar hypoxia. We assessed the extent of HPV in the healthy human lung using inhaled nitric oxide (iNO) under inspired oxygen fractions (FiO2 ) of 0.125, 0.21, and 0.30 (a hyperoxic stimulus designed to abolish HPV without the development of atelectasis). Dynamic measures of blood flow were made in a single sagittal slice of the right lung of five healthy male subjects using an arterial spin labeling (ASL) MRI sequence, following a block stimulus pattern (3 × 60 breaths) with 40 ppm iNO administered in the central block. The overall spatial heterogeneity, spatiotemporal variability, and regional pattern of pulmonary blood flow was quantified as a function of condition (FiO2 × iNO state). While spatial heterogeneity did not change significantly with iNO administration or FiO2 , there were statistically significant increases in Global Fluctuation Dispersion, (a marker of spatiotemporal flow variability) when iNO was administered during hypoxia (5.4 percentage point increase, P = 0.003). iNO had an effect on regional blood flow that was FiO2 dependent (P = 0.02), with regional changes in the pattern of blood flow occurring in hypoxia (P = 0.007) and normoxia (P = 0.008) tending to increase flow to dependent lung at the expense of nondependent lung. These findings indicate that inhaled nitric oxide significantly alters the distribution of blood flow in both hypoxic and normoxic healthy subjects, and suggests that some baseline HPV may indeed be present in the normoxic lung.

Saudi guidelines on the diagnosis and treatment of pulmonary hypertension: 2014 updates

The Saudi Association for Pulmonary Hypertension (previously called Saudi Advisory Group for Pulmonary Hypertension) has published the first Saudi Guidelines on Diagnosis and Treatment of Pulmonary Arterial Hypertension back in 2008.[1] That guideline was very detailed and extensive and reviewed most aspects of pulmonary hypertension (PH). One of the disadvantages of such detailed guidelines is the difficulty that some of the readers who just want to get a quick guidance or looking for a specific piece of information might face.

All efforts were made to develop this guideline in an easy-to-read form, making it very handy and helpful to clinicians dealing with PH patients to select the best management strategies for the typical patient suffering from a specific condition. This Guideline was designed to provide recommendations for problems frequently encountered by practicing clinicians involved in management of PH. This publication targets mainly adult and pediatric PH-treating physicians, but can also be used by other physicians interested in PH.

Updated treatment algorithm of pulmonary arterial hypertension

The demands on a pulmonary arterial hypertension (PAH) treatment algorithm are multiple and in some ways conflicting. The treatment algorithm usually includes different types of recommendations with varying degrees of scientific evidence. In addition, the algorithm is required to be comprehensive but not too complex, informative yet simple and straightforward. The type of information in the treatment algorithm are heterogeneous including clinical, hemodynamic, medical, interventional, pharmacological and regulatory recommendations. Stakeholders (or users) including physicians from various specialties and with variable expertise in PAH, nurses, patients and patients' associations, healthcare providers, regulatory agencies and industry are often interested in the PAH treatment algorithm for different reasons. These are the considerable challenges faced when proposing appropriate updates to the current evidence-based treatment algorithm.The current treatment algorithm may be divided into 3 main areas: 1) general measures, supportive therapy, referral strategy, acute vasoreactivity testing and chronic treatment with calcium channel blockers; 2) initial therapy with approved PAH drugs; and 3) clinical response to the initial therapy, combination therapy, balloon atrial septostomy, and lung transplantation. All three sections will be revisited highlighting information newly available in the past 5 years and proposing updates where appropriate. The European Society of Cardiology grades of recommendation and levels of evidence will be adopted to rank the proposed treatments.

Oral l-citrulline malate in patients with idiopathic pulmonary arterial hypertension and Eisenmenger Syndrome: a clinical trial

BACKGROUND AND PURPOSE

Citrulline is an amino acid which is produced by the urea cycle and also a precursor for NO, that is, a vasodilator for normal function of pulmonary vasculature. Thereby, enhancing l-citrulline malate in patients with idiopathic pulmonary arterial hypertension and those with congenital heart disease identified as Eisenmenger Syndrome results in reduction of pulmonary hypertension.

METHODS AND SUBJECTS

In this clinical trial before and after study, we assigned 25 patients with arterial pulmonary hypertension (idiopathic or Eisenmenger Syndrome) to receive l-citrulline malate 1g three times daily for two weeks. The primary measurement was the change in exercise capacity, as considered as a result of the total distance walked in six minutes, from baseline to week 2. We also assessed mean pulmonary artery pressure, the change in the quality of life, and the change in pro-brain natriuretic peptide (BNP) level. The study was not powered to evaluate mortality.

RESULTS

The mean walking distance in six minutes was significantly increased by about 44m (p=0.005) after receiving l-citrulline malate. Mean pulmonary artery pressure significantly reduced from 83.34mmHg before receiving l-citrulline malate to 79.1mmHg after that (p=0.01). All dimensions of the quality of life had statistical differences after receiving l-citrulline malate except limit due to physical health, limit due to emotional health and social functioning (p>0.05). Finally, pro-BNP difference was not statistically significant (p=0.9).

CONCLUSION

l-Citrulline malate improves the distance walk in six minutes and also the quality of life of patients with idiopathic arterial pulmonary hypertension and Eisenmenger Syndrome and also reduced mean arterial pulmonary hypertension.

Iloprost for idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension is a rare but serious and life-threatening disease that leads to right heart failure and death within 2.8 years without specific treatment. This review focuses on the stable prostacyclin analog iloprost, its biologic action and pharmacology and, finally, on its clinical development, efficacy and safety in patients with idiopathic pulmonary arterial hypertension, which led to its approval for this indication. Furthermore, this review assesses the role of iloprost compared with other newly developed drugs, such as the endothelin receptor antagonist bosentan and the phosphodiesterase-5 inhibitor sildenafil, as well as other modes of application of prostacyclin and its analogs for the treatment of idiopathic pulmonary arterial hypertension. Based on the different modes of action of these substances, a combination of these treatments could be most promising for the future.

First successful heart-lung transplantation in Japan: report of a case

Although legislation regarding organ transplantation from brain-dead donors in Japan was approved in 1997, no heart-lung transplantation procedures were performed for some time. Herein, we report the first case of successful heart-lung transplantation in Japan. The recipient was a 35-year-old man with Eisenmenger syndrome, caused by a double outlet right ventricle, who had been suffering hemoptysis and continued NYHA class 3-4 symptoms for 66 months since being registered on the waiting list. He underwent heart-lung transplantation from a 30-year-old donor. The organ ischemic time was 247 min, the postoperative course was uneventful, and the patient was discharged 66 days after the transplant surgery.

Reactive oxygen species as therapeutic targets in pulmonary hypertension

Pulmonary hypertension (PH) is characterized by a progressive elevation of pulmonary arterial pressure due to alterations of both pulmonary vascular structure and function. This disease is rare but life-threatening, leading to the development of right heart failure. Current PH treatments, designed to target altered pulmonary vascular reactivity, include vasodilating prostanoids, phosphodiesterase-5 inhibitors and endothelin-1 receptor antagonists. Although managing to slow the progression of the disease, these molecules still do not cure PH. More effective treatments need to be developed, and novel therapeutic strategies, targeting in particular vascular remodelling, are currently under investigation. Reactive oxygen species (ROS) are important physiological messengers in vascular cells. In addition to atherosclerosis and other systemic vascular diseases, emerging evidence also support a role of ROS in PH pathogenesis. ROS production is increased in animal models of PH, associated with NADPH oxidases increased expression, in particular of several Nox enzymes thought to be the major source of ROS in the pulmonary vasculature. These increases have also been observed in vitro and in vivo in humans. Moreover, several studies have shown either the deleterious effect of agents promoting ROS generation on pulmonary vasculature or, conversely, the beneficial effect of antioxidant agents in animal models of PH. In these studies, ROS production has been directly linked to pulmonary vascular remodelling, endothelial dysfunction, altered vasoconstrictive responses, inflammation and modifications of the extracellular matrix, all important features of PH pathophysiology. Altogether, these findings indicate that ROS are interesting therapeutic targets in PH. Blockade of ROS-dependent signalling pathways, or disruption of sources of ROS in the pulmonary vasculature, targeting in particular Nox enzymes, represent promising new therapeutic strategies in this disease.

WHO Group 1 pulmonary arterial hypertension: current and investigative therapies

Major advances have been made in the treatment of World Health Organization Group 1 pulmonary arterial hypertension (PAH). Since the mid-1990s, nine medications have become available in the United States to target three key pathophysiologic derangements in PAH - the prostacyclin, endothelin, and nitric oxide pathways. As a group, these agents have led to improvements in functional capacity, symptoms, hemodynamics, and survival. Most patients with mild to moderate PAH are started on orally active agents such as endothelin receptor antagonists or phosphodiesterase inhibitors. Patients with more severe disease, particularly those with evidence of right heart failure, should be treated with continuous prostacyclin infusion or a combination of a prostacyclin and oral therapy. Each medication has unique properties and clinical considerations, and the selection of an appropriate therapy must be tailored to the individual patient. None of the currently available WHO Group 1 PAH therapies are curative, however, and it is the hope that new therapies in development may halt or reverse disease progression. This review will discuss the major therapeutic classes of presently available medications and their role in managing the patient with PAH. We will also review data supporting the use of combination therapy, adjuvant background therapy, and new agents currently under investigation.

Inhalation therapy to treat pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease of the pulmonary vascular system, which may lead to right-heart failure or early death in the absence of effective treatment. The current therapy for PAH mainly includes phosphodiesterase inhibitors, prostanoids and endothelin receptor antagonists. These, however, have adverse effects when administered via conventional routes. There is a clear and critical need for the development of a novel delivery system that can efficiently deliver the drug to lung vasculature and minimize adverse effects. This article summarizes the inhalation devices and recent patents in the area of inhalable therapy for the treatment of PAH. Various patents are discussed that describe the application of inhalable therapy to target lung vasculature and to reduce dose-related side effects in PAH treatment. Entry of some inhalable delivery approaches into clinical trials is the result of progress in inhalable therapies for the treatment of PAH.

Survival in childhood pulmonary arterial hypertension: insights from the registry to evaluate early and long-term pulmonary arterial hypertension disease management

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare but important cause of morbidity and mortality in children.

METHODS AND RESULTS

We analyzed data from 216 patients ≤18 years of age at diagnosis who were enrolled in the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL). Median age at diagnosis and enrollment was 7 and 15 years, respectively. The most frequent presenting symptom was dyspnea (idiopathic/familial PAH, 53%; PAH associated with congenital heart disease, 30%). Presyncope/syncope was more frequent in patients with idiopathic PAH/familial PAH (36%) than in those with PAH associated with congenital heart disease (4%). At diagnosis, mean pulmonary artery pressure and pulmonary vascular resistance index were 56 mm Hg and 17 Wood units · m(2), respectively. Five-year survival from diagnosis for the overall cohort was 74±6%, with no significant difference between the idiopathic PAH/familial PAH (n=122, 75±7%) and PAH associated with congenital heart disease (n=77, 71±13%) cohorts (P=0.53). Older age at diagnosis was the only variable significantly associated with decreased survival from diagnosis. Variables at enrollment that were significantly associated with decreased survival from enrollment included higher pulmonary vascular resistance index, lower-weight z scores, and familial PAH. Additional variables at enrollment, identified in a secondary analysis, that were marginally associated with increased survival from enrollment included acute vasoreactivity (adaptation of conventional pediatric definition; P=0.087) and lower brain natriuretic peptide (P=0.060). None of the 22 patients who were acute responders treated with high-dose calcium channel blockade as monotherapy or combination therapy died within 5 years of diagnosis.

CONCLUSION

Using REVEAL, we identified key predictors of survival in childhood PAH. Refining these prognostic parameters should help clinicians improve outcomes.

CLINICAL TRIAL REGISTRATION

URL: www.clinicaltrials.gov. Unique identifier: NCT00370214.

The Adult Patient with Eisenmenger Syndrome: A Medical Update after Dana Point Part II: Medical Treatment - Study Results

Eisenmenger syndrome is the most severe form of pulmonary arterial hypertension and arises on the basis of congenital heart disease with a systemic-to-pulmonary shunt. Due to the chronic slow progressive hypoxemia with central cyanosis, adult patients with the Eisenmenger syndrome suffer from a complex and multisystemic disorder including coagulation disorders (bleeding complications and paradoxical embolisms), renal dysfunction, hypertrophic osteoarthropathy, heart failure, reduced quality of life and premature death.

For a long time, therapy has been limited to symptomatic options or lung or combined heart-lung transplantation. As new selective pulmonary vasodilators have become available and proven to be beneficial in various forms of pulmonary arterial hypertension, this targeted medical treatment has been expected to show promising effects with a delay of deterioration also in Eisenmenger patients. Unfortunately, data in Eisenmenger patients suffer from small patient numbers and a lack of randomized controlled studies.

To optimize the quality of life and the outcome, referral of Eisenmenger patients to spezialized centers is required. In such centers, specific interdisciplinary management strategies of physicians specialized on congenital heart diseases and PAH should be warranted.

This medical update emphasizes the current diagnostic and therapeutic options for Eisenmenger patients with particularly focussing on the medical treatment and corresponding study results.

Pregnancy and pulmonary hypertension

When pulmonary hypertension (PH) occurs in pregnancy, physiologic stress can overwhelm an already strained right ventricle resulting in right ventricular failure and death. Mortality remains unacceptably high (25%-30%). Patients with PH should be counseled to avoid pregnancy. This article discusses the physiologic changes of pregnancy that make it difficult for patients with PH, the pitfalls of transthoracic echocardiography in diagnosing PH in pregnancy, and the historical data regarding mortality. The causes of development of PH during pregnancy are discussed, and the limited data on management of patients with PH who choose to carry their pregnancy to term are reviewed.

Pulmonary arterial hypertension: a comparison between children and adults

The characteristics of pulmonary arterial hypertension (PAH), including pathology, symptoms, diagnosis and treatment are reviewed in children and adults. The histopathology seen in adults is also observed in children, although children have more medial hypertrophy at presentation. Both populations have vascular and endothelial dysfunction. Several unique disease states are present in children, as lung growth abnormalities contribute to pulmonary hypertension. Although both children and adults present at diagnosis with elevations in pulmonary vascular resistance and pulmonary artery pressure, children have less heart failure. Dyspnoea on exertion is the most frequent symptom in children and adults with PAH, but heart failure with oedema occurs more frequently in adults. However, in idiopathic PAH, syncope is more common in children. Haemodynamic assessment remains the gold standard for diagnosis, but the definition of vasoreactivity in adults may not apply to young children. Targeted PAH therapies approved for adults are associated with clinically meaningful effects in paediatric observational studies; children now survive as long as adults with current treatment guidelines. In conclusion, there are more similarities than differences in the characteristics of PAH in children and adults, resulting in guidelines recommending similar diagnostic and therapeutic algorithms in children (based on expert opinion) and adults (evidence-based).

[COPD and inflammation: statement from a French expert group. Phenotypes related to inflammation]

INTRODUCTION

The objective of the present article is to review available data on possible links between phenotypes and inflammatory profiles in patients with chronic obstructive pulmonary disease (COPD).

BACKGROUND

Chronic bronchitis is associated with proximal bronchial inflammation and small airway inflammation with remodeling at the site of obstruction. CT scanning enables patients to be phenotyped according to the predominantly bronchial or emphysematous nature of the morphological abnormality. Exacerbations, in a context of persistently elevated baseline inflammation, are associated with increased inflammation and a poor prognosis. Long-term studies have correlated inflammatory markers (and anti-inflammatory drug effects) with dynamic hyperinflation, possibly confirming that inflammation promotes hyperinflation. The inflammatory cell count in the pulmonary arterial walls correlates with the severity of endothelial dysfunction. The risk of developing pulmonary hypertension would seem to increase with low-grade systemic inflammation. The role of low-grade systemic inflammation in COPD co-morbidities, and in nutritional and muscular involvement in particular, remains a matter of debate. Regular physical exercise may help reduce this inflammation.

CONCLUSIONS

In COPD, many aspects of the clinical phenotype are related to inflammation. Better knowledge of these relationships could help optimize current and future treatments.

A phase III, multicenter, collaborative, open-label clinical trial of sildenafil in Japanese patients with pulmonary arterial hypertension

BACKGROUND

There is evidence that phosphodiesterase type-5 is effective for the treatment of pulmonary arterial hypertension (PAH).

METHODS AND RESULTS

A phase III, multicenter, open-label clinical trial of sildenafil 20mg t.i.d. was conducted in 21 Japanese patients with PAH to examine its efficacy, safety, and pharmacokinetics. The present trial consisted of a screening period and 12-week treatment. Patients who were enrolled in the present trial increased their 6-min walking distance of administration increased at week 12 by 84.2m from baseline. Hemodynamic parameters (eg, mean pulmonary artery pressure and pulmonary vascular resistance), Borg dyspnea scores, and plasma brain natriuretic peptide concentrations also improved compared to baseline. Most patients improved or sustained WHO functional class. Seven subjects, who were examined for the pharmacokinetics of sildefanil, showed relatively large interindividual variations in the C(max), AUC(0-8), C(ss,av), and C(trough) of the drug. Any serious adverse events, severe adverse events, and deaths were not observed. Most of events of undeniable causality were mild or moderate in severity. Sildefanil was well tolerated by the subjects.

CONCLUSIONS

Sildenafil 20mg t.i.d. was effective and safe for Japanese patients with PAH.

Long-term outcomes in children with pulmonary arterial hypertension treated with bosentan in real-world clinical settings

Treatment algorithms in pediatric pulmonary arterial hypertension (PAH) are derived from clinical trials in adult populations and from clinical practice, but experience in children is limited. In this retrospective cohort study, we analyzed outcomes in a previously identified cohort of 86 consecutive children with PAH treated with bosentan as part of their treatment regimen. All children with idiopathic PAH or heritable PAH and PAH associated with congenital heart disease or connective tissue disease who started bosentan treatment from May 2001 to April 2003 in 2 tertiary pediatric referral centers were followed, with data collection ending August 2006. Eighty-six children (37 male, 49 female) 11 ± 5 years of age with idiopathic/heritable PAH (n = 36), PAH associated with congenital heart disease (n = 48), or PAH associated with connective tissue disease (n = 2) received bosentan as monotherapy (n = 42) or as an add-on to pre-existing continuous intravenous epoprostenol or subcutaneous treprostinil (n = 44). Median observation period was 39 months (range 2 to 60). Thirty-four patients (40%) received ≥1 additional PAH-specific therapy during follow-up. At end of data collection, 25 patients (29%) remained on bosentan, 43 (50%) had stopped bosentan, 11 (13%) had died while on bosentan, and 7 were lost to follow-up. At 4 years, the Kaplan-Meier estimate of disease progression in patients while on bosentan was 54% (7 patients at risk) with a survival estimate of 82% (16 patients at risk). Risk factors significantly associated with survival were World Health Organization functional class and indexed pulmonary vascular resistance. In conclusion, outcome in children with PAH managed with current treatment regimens appears favorable. However, despite current therapy options, disease progression remains a concern.

Outcome of pediatric patients with pulmonary arterial hypertension in the era of new medical therapies

Little is known about the effects of "second-generation drugs" (prostanoids, endothelin receptor antagonists, 5-phosphodiesterase inhibitors) in children with pulmonary arterial hypertension (PAH). This study describes the outcome of a national cohort of children with PAH in an era when these drugs became available. From 1993 to 2008, 52 consecutive children with idiopathic PAH (n = 29) or systemic-to-pulmonary shunt-associated PAH (n = 23) underwent baseline and follow-up assessments. Treatment was initiated depending on functional class, acute pulmonary vasoreactivity response, and drug availability. Observed survival was evaluated depending on time of diagnosis in relation to second-generation drug availability and subsequently compared to calculated predicted survival. Children for whom second-generation drugs were available had improved survival compared to their predicted survival (1-, 3-, and 5-year survival rates 93%, 83%, and 66% vs 79%, 61%, and 50%, respectively). However, this improved survival was observed only in patients for whom second-generation drugs became available during their disease course. No improved survival was observed in patients for whom drugs were available already at diagnosis. Baseline variables associated with decreased survival included higher functional class, higher pulmonary-to-systemic arterial pressure ratio, lower cardiac index, and higher serum levels of N-terminal pro-brain natriuretic peptide and uric acid. After start of second-generation drugs, functional class, 6-minute walking distance, and N-terminal pro-brain natriuretic peptide improved but gradually decreased after longer follow-up. In conclusion, survival of pediatric PAH seemed improved since the introduction of second-generation drugs only in selected patients for whom these drugs became available during their disease course. Start of second-generation drugs initially induced clinical improvements, but these effects decreased after longer follow-up.

Advances in hemophilia: experimental aspects and therapy

This article describes recent clinical and research advances in hemophilia therapy. Different prophylactic regimens for the management of severe hemophilia are described along with the use of adjuvant treatment options to achieve hemostasis. The safety and efficacy of radionuclide synovectomy with phosphorus 32-sulfur colloid to treat existing joint arthropathy also are described. The development of inhibitors to factor VIII or IX remains a challenge for hemophilia care and recent approaches to achieve immune tolerance induction are discussed. Finally, recent advances in hemophilia are mentioned, including the role of iron, inflammation, and angiogenesis in the pathogenesis of hemophilic arthropathy.

Clinical efficacy of sildenafil in treatment of pulmonary arterial hypertension in dogs

BACKGROUND

Pulmonary arterial hypertension (PAH) in dogs carries a poor prognosis. Sildenafil increases exercise capacity and improves hemodynamics in people with PAH.

HYPOTHESIS/OBJECTIVES

Dogs receiving sildenafil will have lower pulmonary arterial pressure, increased exercise capacity, and better quality of life (QOL) than dogs receiving placebo.

ANIMALS

Thirteen dogs with echocardiographic evidence of PAH.

METHODS

Prospective short-term, randomized, placebo controlled, double-blind, crossover study. Dogs with PAH were randomly allocated to receive sildenafil or placebo for 4 weeks, followed by the alternative treatment for 4 weeks.

RESULTS

Dogs receiving sildenafil had a significantly lower estimated pulmonary arterial pressure (median, 56 mmHg; range, 34-83 mmHg) than at baseline (median, 72 mmHg; range, 61-86 mmHg; P=.018), but not significantly lower than those receiving placebo (median, 62 mmHg; range, 49-197 mmHg). Exercise capacity was significantly greater in dogs receiving sildenafil than those receiving placebo (mean activity count per minute: 101+/-47 versus 74+/-32; P=.05). QOL scores were significantly higher in dogs receiving sildenafil than dogs receiving placebo.

CONCLUSIONS AND CLINICAL IMPORTANCE

Sildenafil decreases systolic pulmonary arterial pressure from baseline in dogs with PAH and is associated with increased exercise capacity and QOL when compared to treatment with placebo.

Acute and long-term effects of inhaled iloprost in portopulmonary hypertension

Portopulmonary hypertension (PoPH) is a serious condition without an established treatment. Drugs used to treat pulmonary hypertension may have detrimental effects on portal hypertension. This study was designed to assess in patients with PoPH the acute effects of inhaled iloprost (iILO) on pulmonary and hepatic hemodynamics and to evaluate the clinical outcome after 12 months of treatment. We conducted 2 separate studies. In the first one, 21 patients with PoPH were acutely tested with 2.8 microg of iILO. Pulmonary and hepatic hemodynamics were assessed at the baseline and through 60 minutes after iILO. In the second one, we retrospectively evaluated 12 patients treated with iILO (30 microg/day) for more than 1 year. The 6-minute walk distance (6MWD), functional class (FC), and echocardiogram were analyzed at the baseline and after 12 months of treatment. In the acute study, iILO rapidly reduced pulmonary artery pressure (PAP; -16% + or - 8%, P < 0.001) and pulmonary vascular resistance (-18% + or - 14%, P < 0.001). The cardiac output did not change initially but decreased after 30 minutes. The hepatic venous pressure gradient (HVPG) and hepatic blood flow did not vary through the study. Pulmonary vasodilation induced by iILO was inversely related to HVPG. In the long-term evaluation, iILO improved FC by 1 or more in 7 patients (P = 0.04) and increased 6MWD by 67 + or - 59 m at 12 months (P < 0.001). No change in systolic PAP was observed. Two patients died because of hepatic complications, and 4 additional patients presented clinically significant events that were related to hepatic disease in 2 and worsening of pulmonary hypertension in 2. We conclude that in patients with PoPH, iILO produces rapid and selective pulmonary vasodilation without altering the hepatic hemodynamics. Its long-term use may provide sustained improvements in symptoms and exercise tolerance in some patients with PoPH. A randomized, controlled trial is warranted to establish its clinical role in this serious condition.

Addition of prostanoids in pulmonary hypertension deteriorating on oral therapy

BACKGROUND

The aim of our study was to describe the efficacy of addition of intravenous or subscutaneous prostanoids in idiopathic pulmonary arterial hypertension (PAH) patients deteriorating on bosentan or on bosentan-sildenafil.

METHODS

PAH treatment at our hospital is standardized with first-line oral therapy in New York Heart Association class III patients followed by addition of prostanoids on clinical worsening.

RESULTS

Mean improvement in 6-minute walk distance after 4 months of prostanoids was 86 m (p < 0.01) in the bosentan group versus 41 m (p < 0.05) in the bosentan-sildenafil group, and these improvements persisted at long-term follow-up.

CONCLUSIONS

From these results we conclude that addition of subcutaneous or intravenous prostanoids can be efficacious in PAH deteriorating on oral therapy.

Bleeding events in pulmonary arterial hypertension

Despite limited evidence from clinical studies, anticoagulant drugs such as vitamin K antagonists (VKA) (e.g., warfarin or phenprocoumon) are widely used in the background treatment of patients with pulmonary arterial hypertension (PAH). According to current guidelines, they are generally accepted as efficacious drugs, although their efficacy is neither supported by randomised controlled trials, nor formally approved by regulatory agencies for use in the specific PAH indication. The use of these drugs is not without problems, as a paradoxical situation has to be managed in the treatment of this condition. On one hand, thrombosis is one of the key pathophysiologic features of PAH (besides vasoconstriction, proliferation and inflammation). On the other hand, the incidence of bleeding events is increased in PAH patients. This applies particularly to PAH that is related to connective tissue diseases, congenital heart disease and chronic thromboembolic pulmonary hypertension. In patients receiving VKA, caution must be observed in particular when concomitantly using prostanoids or sildenafil. Similarly, VKA doses have to be adjusted according to the labelling when using sitaxentan concomitantly. Regular International Normalized Ratio monitoring contributes to the safety of PAH patients on VKA.